A standard ring-spinning or -twisting machine has a spindle bank on which a plurality of upright spindles arranged in a row are rotatable about vertical axes. These spindles normally carry sleeves or quills on which respective yarns or rovings are wound to form the desired yarn packages or cops. The yarns run over ring guides or the like to the respective spindles.
Once a package is complete, the respective guide drops down to a level below the sleeve and winds several turns of the yarn around a lower reserve surface on the respective spindle that is knurled to prevent the yarn from slipping on it. When the sleeve is subsequently doffed, the yarn breaks, leaving the leading end of the incoming yarn wound around the lower reserve surface of the spindle. Then a new spindle is set in place and the winding operation starts again with the yarn caught on the lower reserve surface being caught on the new sleeve and wound up, repeating the cycle.
Clearly a problem with this system is that the reserve surface quickly gets fouled with the yarn, since several turns are added each time the sleeve is changed. These reserve surfaces must be cleared periodically. U.S. Pat. Nos. 3,312,051, 4,094,134, 5,311,732, and 5,319,917 and German patent document 2,461,621 describe apparatuses which rub, brush, and/or scrape the windings off the reserve surface.
While ideally the reserve surface should be cleaned thoroughly each time the cop is doffed, in reality it is fairly difficult to get all the yarn off it. The problem is that the knurling of the reserve area is formed in the traditional way with a knurling tool formed with a succession of pyramid-shaped recesses flanked by a pair of ridges. Thus the resultant knurling is constituted as an array of pyramid-shaped points separated by annularly continuous or helical grooves. The filament lodges readily in these grooves and whatever tool is being used to remove the yarn windings on the reserve surface has a hard time getting it out.
Japanese patent document 60-21923 of 4 February 1985 of Fukuda proposes flattening the tops of the normally pointed bumps produced by knurling. Such an arrangement still leaves annular or helical grooves in which the yarn can lodge. In addition U.S. Pat. No. 4,543,778 of Koella decribes a system for laying the yarn on the reserve system in a particularly easy-to-remove pattern, but even so this arrangement allows the yarn to lodge in the knurling.